noun - Brackish water or briny water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak", meaning "salty".
Seawater is water from a sea or ocean. It is salt water. On average, seawater in the world's oceans has a salinity of about 3.5% (35 g/L, or 599 mM). Seawater is denser than fresh water. The freezing point of seawater decreases as salt concentration increases. At typical salinity it freezes at about −2 °C (28 °F).
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and other total dissolved solids. The term "sweet water" has been used to describe fresh water in contrast to salt water.